000
AXPZ20 KNHC 050216 CCA
TWDEP 

Tropical Weather Discussion...Corrected
NWS National Hurricane Center Miami FL
2205 UTC Mon Sep 4 2017

Tropical Weather Discussion for the eastern Pacific Ocean from
the Equator to 32N, east of 140W. The following information is
based on satellite imagery, weather observations, radar, and
meteorological analysis.

Based on 1800 UTC surface analysis and satellite imagery through
2145 UTC.
  
...TROPICAL WAVES...

A tropical wave axis extends from 22N109W 17N112W to 11N114W,
moving westward at 10 to 15 kt. Scattered moderate convection is
seen within 180 nm either side of the axis from 15N to 18N.

..INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... 

The monsoon trough axis extends from NW Colombia to 09N84W 
to low pressure near 13N128W 1012 mb to 13N140W. Scattered 
moderate isolated strong convection is within 120 nm S of the
axis between 90W and 92W, and within 30 nm of the axis between 
128W and 130W. Scattered moderate convection is within 180 nm 
S of the axis between 130W and 135W, and within 60 nm of the axis
between 85W and 88W.
 
...DISCUSSION...

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

The eastern periphery of a weak ridge over the NW portion of the
discussion area will build eastward Tuesday night and persist 
through Thursday. The pressure gradient between this ridge and 
lower pressure over Mexico will support mainly gentle to moderate
NW winds, and seas of 3 to 5 ft across these waters through 
Tuesday. The pressure gradient will tighten Tuesday night through
Thursday as the ridge builds eastward, resulting in moderate to 
fresh winds west of Baja California Norte with seas of 5 to 7 ft.

Farther south, fresh to strong overnight gap winds are possible 
through the Gulf of Tehuantepec beginning late Thursday night, 
with seas building to near 7 ft. Otherwise, light to gentle 
winds and seas of 4 to 6 ft will prevail.

OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND 
WITHIN 750 NM OF ECUADOR...

Light and variable winds are expected N of the monsoon trough 
through Tuesday, with moderate to locally fresh southerly winds 
expected S of the monsoon trough with 4 to 6 ft seas over the 
entire area through Thursday. By Friday the southerly winds are 
forecast to increase slightly to the south of the monsoon trough,
building seas to 6 to 8 ft across that area Friday and into next
weekend. 

REMAINDER OF THE AREA...

A weak 1019 mb high is analyzed near 25N137W, with a ridge 
extending E to near 120W. The pressure gradient between the high 
and lower pressure associated with the monsoon trough will 
maintain mainly gentle to moderate trades N of the monsoon 
trough and W of 120W, with seas remaining 4 to 6 ft through 
Friday. A pocket of moderate to fresh trades is expected between 
the 1012 mb low and the ridge, gradually shifting westward to
near 140W by Friday, with seas of about 5 to 7 ft. Seas are 
expected to build to 6 to 8 ft over the far western portion of
the area on Thursday from about 15N to 20N as the gradient there
tightens some. Moderate to occasionally fresh SW winds are 
expected S of the monsoon trough through Friday. Long period 
cross-equatorial swell producing combined seas of 7 to 8 ft in 
SW waters today will slowly decay through tonight, but will 
remain about 5 to 7 ft through the upcoming week. Isolated 
showers are possible over the far N central portion of the area 
N of 28N between 122W and 127W as low to mid-level moisture 
lingers there in association with a negatively-tilted shortwave 
trough that extends from 32N127W southeastward to near 
27.5N121.5W. The trough will slowly shift eastward through 
Wednesday.

$$
Aguirre